The invention relates to a process for fitting a cylindrical sleeve around a cylindrical roller core, in the free state the sleeve having an internal diameter which is smaller than the external diameter of the roller core, by changing the diameter of the sleeve and the core relative to each other, using a pressurized medium flowing out on the periphery of the core, in such a way that the sleeve can be slid around the core and, when the sleeve and the core are in the desired position relative to each other, ending the supply of medium, thereby causing the sleeve and the core to mate tightly, the sleeve being impermeable to pressurized medium at least during the operation of fitting the sleeve round the core.
Such a process is known from European Patent Application No. 85 200 621.2 of Applicants.
The above-mentioned application describes a process in which a relatively thin-walled cylindrical, seamless perforated sleeve is fitted on the surface of a cylindrical roller core. For carrying out the above-mentioned process, in a suitable embodiment the perforations of the perforated material used, for example a metal rotary silk-screen printing stencil, are temporarily sealed with a material which is impermeable to a gaseous or liquid medium, following which said completely tight sleeve is slid over the cylindrical core with the aid of the medium used, the pressurized medium used serving to expand the sleeve temporarily within the elasticity range during the slide-on operation, so that said sleeve acquires an internal diameter which is greater than the external diameter of the roller core used. The medium used, for example compressed air, in this situation serves both as an expansion agent and as a lubricant for moving the sleeve over the core.
A roller with such a sealed perforated material on the surface is washed with a suitable solvent after the fitting operation, in order to remove the sealing material from the perforations, and this produces a roller with a surface containing a large number of cavities (the perforations of the stencil); such a roller can be used, for example, as an inking or colour application roller in a printing machine.
In the event of the sleeve being unperforated, in this case known as a "blind", a completely closed surface is obtained; such a rigid roller provided with a top layer can also be used in a printing machine, for example as a guide roller with special features which are connected with the type of sleeve.
The known process has the disadvantage that for it to succeed it is necessary for the sleeve to be of limited thickness, i.e. of such thickness that at relatively low and unhazardous pressure of the medium a sufficient diameter increase is achieved.
For sleeve material with thicker walls no suitable unhazardous possibility is offered by this known process.